Generally, a state of the art hearing aid, such as, for example, disclosed in US patent application no.: 2005/0244026, comprises a flexible earpiece to be inserted into the outer part (sometimes referred to as cartilaginous or softer region) of the ear canal and connected to a BTE device through a connecting tubular element. The flexible earpiece may comprise a receiver, i.e. a hearing aid speaker, mounted on to the earpiece so as to inject sound into the ear canal. This configuration is general known as receiver-in-the-ear (RITE) hearing aid. Alternatively, the BTE comprises the receiver and the sound is injected into the tubular connector communicating the sound to the earpiece.
The flexible earpiece may additionally comprise a vent so as to provide an open ear configuration thereby reducing occlusion effects but significantly reducing the allowable gain at which acoustical feedback occurs. Hence the flexible earpiece is particularly for use when hearing impairment of the user of the hearing aid is mild.
Further, U.S. Pat. No. 5,606,621 discloses a hybrid BTE and completely-in-canal (CIC) hearing aid, where the earpiece is implemented as a CIC element shaped to into the ear canal in such a manner to touch the bony region of the ear canal. By inserting the CIC element deep into the bony region of the ear canal occlusion effect may be avoided while a high gain still may be maintained, since sound communicated through the tissue into the ear canal (instead of from ear opening) may freely escape the ear canal. Hence this hybrid BTE/CIC hearing aid provides benefits for users having a greater hearing impairment.
In addition, US patent application no.: 2004/0010181 discloses another hybrid BTE/CIC hearing aid comprising a connector for communicating the processed sound from a processor in the BTE to a speaker in the CIC part. The connector is detachably connected to either the BTE or CIC part and is designed to be inserted in ear canal so deep as to touch the bony part of the ear canal. The connector therefore must be sufficiently rigid to allow the connector to be used to insert and remove the CIC part from the ear canal of the user.
The U.S. Pat. No. 5,606,621 and US patent application no.: 2004/0010181 basically describe closed systems, i.e. systems, which when positioned in the outer region of the ear canal causes severe occlusion effects, which are caused by encapsulating sound conducted via tissue to the residual space between the tympanic member and closed system earpiece. Hence the purpose of the hearing aids described in these U.S. patent documents is to position the CIC parts in the bony part or the inner most part of the ear canal thereby avoiding occlusion effect, which is not transmitted to the bony part of the ear canal. However, for users the insertion into the bony part of the ear canal may seem rather intrusive.